For example, Patent Literature 1 below discloses a method for spraying a chemical solution through a spray nozzle in order to coat the chemical solution on substantially the entire region of the inside surface of a tubular blood testing container. The spray nozzle includes an outer tube and an inner tube inserted in the outer tube. The chemical solution is fed to the inner tube and a gas is fed to a space between the outer and inner tubes.
In use, the tip of the spray nozzle is inserted into the blood testing container, and in this state the chemical solution and gas are simultaneously supplied into the container. The chemical solution discharged from the distal end of the inner tube is turned into an aerosol by the gas, so that the chemical aerosol is sprayed from the tip of the spray nozzle. The chemical aerosol is splashed around by streams of the gas. After the start of spraying, the spray nozzle is moved up in the tubular blood testing container to coat the chemical solution on substantially the entire region of the inside surface of the blood testing container.